package com.example.gulimall.product.service.impl;

import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.common.utils.PageUtils;
import com.example.common.utils.Query;

import com.example.gulimall.product.dao.CategoryDao;
import com.example.gulimall.product.entity.CategoryEntity;
import com.example.gulimall.product.service.CategoryService;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Override
    public List<CategoryEntity> listWithTree() {
        //1、查出所有分类
        List<CategoryEntity> entities = baseMapper.selectList(null);
        //2、组装成父子的树形结构

        //2.1找到所有的一级分类
        List<CategoryEntity> level1Menus = entities.stream().filter((categoryEntity) ->
            categoryEntity.getParentCid() == 0
        ).map((menu)->{
            menu.setChildren(getChildrens(menu,entities));
            return menu;
        }).sorted((menu1,menu2)->{     //给上边找到的菜单的子菜单排序
            return (menu1.getSort()==null ? 0 :menu1.getSort()) - (menu2.getSort()==null ? 0 :menu2.getSort());
        }).collect(Collectors.toList());  //将上边处理过的值收集到list中

        return level1Menus;
    }

    /**
     * 批量删除菜单
     * @param asList
     */
    @Override
    public void removeMenuByIds(List<Long> asList) {
        //todo  1、检查当前删除的菜单，是否被别的地方引用

        //逻辑删除
        baseMapper.deleteBatchIds(asList);
    }

    /**
     *递归查找 获取所有菜单的子菜单
     * @param root  当前菜单
     * @param all 所有菜单
     * @return
     */
    private List<CategoryEntity> getChildrens(CategoryEntity root,List<CategoryEntity> all){

        List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
            return categoryEntity.getParentCid() == root.getCatId();    //过滤 当前菜单的父id == root菜单的id相等，说明当前菜单是root菜单的子菜单
        }).map(categoryEntity -> {
            //每一个菜单有可能还会有子菜单，所以继续调用getChildrens()方法找子菜单，再进行排序
            categoryEntity.setChildren(getChildrens(categoryEntity,all));
            return categoryEntity;
        }).sorted((menu1,menu2)->{
            return (menu1.getSort()==null ? 0 :menu1.getSort()) - (menu2.getSort()==null ? 0 :menu2.getSort());
        }).collect(Collectors.toList());
        return children;
    }

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

}